A conveyor system typically comprises a plurality of rollers and a conveyor belt engaged with the rollers. Such conveyor systems include an upper portion that serves to transport the product carried on the conveyor belt from a first end of the conveyor system to the second end thereof. A lower portion serves as the conveyor belt return pathway, through which the conveyor belt travels from the second end of the conveyor system to the first end thereof. Typically, the return path or lower portion of the conveyor belt is relatively slack. Most clean-in-place systems and/or tensioning system are positioned on the lower portion of the conveyor system since that portion of the conveyor system is not designed to engage the product.
Conveyor systems are widely used in cooling tunnels. Cooling tunnels typically include a housing with a conveyor system therein for moving the product through the cooling tunnel. Blowers or fans provide for moving refrigerated or chilled air and other cooling gases, such as carbon dioxide, over the product. In many applications the conveyor belt is formed with a plurality of apertures to permit flow of the cooled gases through the conveyor belt. The cooled or chilled gases may be introduced by a number of systems including by spraying liquid carbon dioxide into the cooling space to provide chilled air and carbon dioxide gas for cooling. Movement of the gases over the food product is enhanced by exhaust ducts and fans.
Problems are encountered in the operation of such cooling tunnels, particularly with high capacity tunnels providing for high speed movement of the product through the tunnel and for high velocity of cooling gas flow. In such tunnels, the conveyor system may collect and/or trap food particles creating a potentially unsanitary condition. This issue is especially acute in the conveyor return portion of the cooling tunnel as it is typically positioned underneath the main conveyor. This is especially the case in situations where the product positioned on the conveyor belt is “tacky,” (e.g., products such as caramel, sugar solutions, and chocolate nougat), which have a tendency to stick to or collect on the food processing equipment. Contact of a tacky material with the conveyor belt often results in the transfer and/or accumulation of the tacky material on the conveyor return rollers. Accumulation or transfer of the material onto the conveyor return rollers may inhibit proper operation of the conveyor belt, contaminate the conveyor belt and interfere with maintaining the proper tension on the conveyor belt.